LOS ANGELES — The rumblings are early but unmistakable: A political earthquake is — finally — headed to California.

For decades now, Democrats and Republicans here have experienced statewide politics as an interminable waiting game, thanks to a gang of 70- and 80-somethings from the Bay Area who have dominated government for a generation.

In a state famed for its youth and vitality, home to Hollywood and the Silicon Valley gospel of economic “disruption,” boasting an ultra-diverse population that presaged the country’s larger ethnic transformation — California’s leadership looks much the same as it did in the late 20th century.

Rising stars in both parties have come and gone, but the state’s chief power players have remained the same: Jerry Brown, California’s 76-year-old governor, is running for reelection this year to a post he first won in 1974. The two senators — Barbara Boxer, 73, and Dianne Feinstein, 81 — have held their jobs since the early 1990s.

The most prominent member of the congressional delegation, 74-year-old House Minority Leader Nancy Pelosi, started out as chairwoman of the California Democratic Party when Ronald Reagan was president. The current party chairman, 81-year-old John Burton, is a former congressman who first went to Washington in the 1974 post-Watergate revolution.

But at long last, change is afoot in the Golden State.

Democrats here — along with a few tenacious Republicans — say there’s a palpable sense that a changing-of-the-guard moment is approaching. It has already begun in some places, with the retirements of several long-tenured federal lawmakers and the defeat of 16-term Democratic Rep. Pete Stark in a 2012 primary.

For the most part, members of the under-50 crowd in California politics aren’t taking shots at their elders. On the contrary, they praise them for their steady leadership of an often-troubled state even as they brace for a shakeup that may be as few as two years away.

“We’ve had great leadership in Washington and also in Sacramento lately. But look to the next eight, 10 years — it’s going to be a generational shift. The Gen X-ers are going to take over in California,” said Santa Barbara Mayor Helene Schneider, a 43-year-old Democrat.

Longtime Democratic consultant Garry South called it “ironic” that in a state “viewed as a hip trendsetter for the rest of the nation, we’ve got this cast of septuagenarians and octogenarians.”

“I mean, even Catholic bishops have to retire at 75,” South said. “We’ve got such an aging leadership in our party when there’s so much bright young talent on our bench. It’s only a matter of time before the torch is passed.”

The elections this year in California look mostly like a status quo affair: Brown is expected to easily win another term . Neither of the U.S. senators is up for reelection. The hottest statewide race may be a down-ballot contest for superintendent of education that has become a proxy fight between teachers unions and heavily funded reform groups.

Yet the buildup of talent on the Democratic bench means it’s only a matter of time before the state witnesses a genuine free-for-all among feisty younger officeholders. At the latest, that’ll come in 2018, when Brown would run up against the state’s two-term limit on governors; it could happen even sooner if Boxer were to retire in 2016. What’s more, new term limits promise to shake loose entrenched members of the Legislature and start to bring new faces to Sacramento as early as next year.

Even this year, some youthful candidates are testing the limits of California’s surprisingly insurgent-averse political culture. Silicon Valley lawyer Ro Khanna is running a well-financed challenge to veteran Democratic Rep. Mike Honda, while Neel Kashkari, former administrator of the Troubled Asset Relief Program, is playing up his youth in a bid to unseat Brown.

Kashkari’s first TV ad featured the 40-year-old Republican swinging an ax, splitting logs and pledging to cut taxes. In an interview, he said he considered his relative youth part of the larger contrast he’s trying to draw with Brown and his “1970s” ideas.

“In this race, me versus Jerry Brown, the Republican is 40 years old, a brown guy, a son of immigrants. The Democrat is the old white guy [who] inherited millions of dollars from his rich, powerful father,” Kashkari said.

Khanna, a Democrat who filed against Honda under the state’s open-primary system, struck a similar, if softer, chord on the issue of age. “I honestly don’t think age should be a factor in any election,” he said. “What’s relevant is, are the ideas new and innovative to address California’s economy. The campaign really is about the different approach in terms of ideas.”

To a great extent, California’s coming generational turnover may also line up with a geographic shift in state politics. If the upper echelons of Democratic leadership here are unrepresentative in terms of age and race, they also come disproportionately from the San Francisco area.

About 20 percent of the state’s population lives in the San Francisco-San Jose region, according to the U.S. Census. But fully half of California’s people are in the greater Los Angeles area, which has produced only one major Democratic statewide officeholder — recalled ex-Gov. Gray Davis — in a quarter-century. The last U.S. senator from L.A. was John Tunney, who left office before Jimmy Carter was sworn in as president.

When Senate seats and the governorship start to open up again, Democrats say, it’s an opportunity for Southern California as much as it is for the younger Democratic set.

Garcetti, who only just finished his first year in office, said at a POLITICO event last week that Californians had been wise to recognize that “seniority gets us power” in Washington. (“The work that Sens. Boxer and Feinstein have done — we couldn’t ask for a better team.”) He also suggested that a shift in political balance could be coming among the various regions of the state.

“If you want an honest answer, people have always said down here that we don’t have a chip on our shoulder about the North and we always vote for Northerners, but not always vice versa,” Garcetti said. “I think that can change.”

Geography, however, is only one of the many ways in which California’s leadership is out of line with a state that has a median age of 35. Its under-45 population is larger by 3 percent than the nation’s as a whole; California’s Latino population is double that of the rest of the country, and its Asian population is nearly triple.

Burton, the party chairman, called talk of leadership turnover still several years premature: “It’s not something on my radar.” He said he hadn’t yet heard rumblings from candidates laying the groundwork to succeed Brown or the two senators.

“What are they gonna say? ‘I’m thinking of running’? Fine. Call me in four years,” he said. “I’m sure they’re all salivating.”